A conventional lighting fixture as shown in FIG. 11 includes: a lamp such as a fluorescent lamp F pivotally secured to plural links L by pivotal joints J, each link L and each pivotal joint J being resiliently linked by a tension spring S and a lower vertical link rotatably mounted on a clamp C for clamping the lighting fixture on a table by a vertically rotatable joint J1. However, when adjusting the lamp F to any desired orientation and position, a knob K should be rotated to fixedly fasten each joint J to prevent its loosening to thereby cause inconvenience for the lamp user.